Polyepoxysuccinic AcidPESA is a multivariate scale and corrosion inhibitor with non-phosphor and non-nitrogen&comma; it has good scale inhibition and dispersion for calcium carbonate&comma; calcium sulfate&comma; calcium fluoride and silica scale&comma; with effects better than that of ordinary organophosphines&period; When built with organophosphates&comma; the synergism effects are obvious&period;PESA has good biodegradation properties&comma; it can be widely used in circulating cool water system in situation of high alkaline&comma; high hardness and high pH value&period; PESA can be operated under high concentration index&period; PESA has good synergism with chlorine and other Water Treatment Chemicals&period;